Simple math formula

A1=39.7
B1=38.6 - 68.9
Here, Cell A1 contains single data but B1 data is together & that is separated by dash, so from here I need to solve below calculations

C1=38.6-68.9= -30.3
D1=39.7-68.9= -29.2

E1=((38.6-68.9)/68.9)%     (i.e  -0.44% )
F1=((39.7-68.9)/68.9)%     (i.e  -0.42%)

hi Jakobshavn,Excellent salvation, thanks for you time...

hi Jakobshavn , need little bit modified your formula. here RIGHT(B1,4) this logic is not applicable for all time as the data change all time
C1=20.31-125.65= -105.34

got solution like :

C1=LEFT(B1,SEARCH("-",B1)-1)-MID(B1,SEARCH("-",B1)+1,LEN(B1)-SEARCH("-",B1))